BBIO 302 Human Anatomy and Physiology Lecture Notes - PDF

BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Chapter ii. cells The nucleus Cells Located in the middle. Structural units of all living things. It is the control center of the cell....

BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Chapter ii. cells The nucleus Cells Located in the middle. Structural units of all living things. It is the control center of the cell. Contained genetic material known as The human body had 50 to 100 trillion deoxyribonucleic acid (DNA). cells. DNA is needed for building Cellular basis of life proteins. Cell theory DNA is necessary for cell reproduction. The cell is the basic structural and functional unit of living organisms. The activity of an organism depends on the collective activity of it cells. It forms tissues, tissues for organs, organs have specific functions. According to the principle of complementarity, the biochemical activities of cells are dictated by their structure (anatomy) which determines their function (physiology). Continuity of life has a cellular basis. Nuclear Envelope (membrane) Apoptosis- programmed cell death. Occurs naturally. Consists of a double membrane that Necrosis- death of cells due to stimuli. binds the nucleus. E.g. fire or infection. Contains nuclear pores that allow for the Composition of cells exchange of material with the rest of the cell. Carbon- 11% Encloses the jellylike fluid called the Hydrogen- 59% nucleoplasm. Oxygen- 24% Nitrogen- 3-4% Nucleolus Cells are about 60-80% water. Contains one or more dark-staining nucleoli. Anatomy of a generalized cell Sites of ribosome assembly. Ribosomes migrate into the cytoplasm through nuclear pores to serve as the site of protein synthesis. Chromatin Composed of DNA wound around histones (proteins). Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Scattered throughout the nucleus and Role of proteins present when the cell is not dividing. Responsible for specialized membrane Condenses to form dense, rodlike bodies functions: called chromosomes when cell divides. Enzymes The plasma membrane Receptors for hormones and other chemical messengers Transparent barrier for cell contents. Transport as channels or carriers Contains and separated cell contents from surrounding environment. Proteins are made up of amino acids. Role of sugars Glycoproteins are branched sugars attached to proteins that abut the extracellular space. Fluid mosaic model Two layers of phospholipids arranged tail to tail. Cholesterol and proteins are scattered Glycocalyx is the fuzzy, sticky, sugar-rich among the phospholipids. area on the cell’s surface. Sugar groups may be attached to the Cell membrane junctions phospholipids forming glycolipids. Phospholipids are polar molecules. The Cells are bound together in three ways; charged end interacts with water which the Glycoproteins in the glycocalyx act as an adhesive or cellular glue. fatty acid chains do not. This polarity Wavy contours of the membranes of makes phospholipids a good foundation for adjacent cells fit together in a tongue-and- cell membranes. groove fashion. Phospholipid arrangement Special cell membrane junctions are formed, which vary structurally depending Hydrophilic on their roles. (water loving) polar heads Main types of junctions are oriented on the inner and outer surfaces of the membrane. Hydrophobic (water fearing) nonpolar tails form the center (interior) of the membrane. This makes the plasma membrane relatively impermeable to most water-soluble molecules. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Tight Junctions Three major component of the Impermeable junctions. cytoplasm Bind cells together into leakproof sheets. Cytosol Plasma membranes fuse like a zipper to prevent substances from Fluid that suspends other elements and passing through extracellular space contains nutrients and electrolytes. between cells. Inclusions Desmosomes Chemical substances, such as stored Anchoring junctions, like rivets, nutrients or cell products, that float in the that prevent cells from being pulled cytosol. apart as a result of mechanical stress. Organelles Created by buttonlike thickenings of adjacent plasma membranes. Metabolic machinery of the cell that perform functions for the cell. Gap junctions (communicating junctions) Many are membrane-bound, allowing for Allow communication between compartmentalization of their function. cells. Hollow cylinders of proteins (connexons) span the width of the abutting membranes. Molecules can travel directly from one cell to the next through these channels. The cytoplasm Cell physiology Cells have the ability to; Metabolize Digest Food Dispose of Wastes The cellular material outside the nucleus and inside the plasma Reproduce membrane. Grow Site of most cellular activities. Move Includes cytosol, inclusions, and organelles. Respond to Stimulus Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Cell extensions Fibroblast Secretes cable like fibers. Is used for Surface extensions found in some cells. wound healing and usually seen on the Also known as accessories. skin. Cilia Erythrocyte (RBC) Move materials across the cells surface. Bi-concave disks that carried oxygen in the bloodstream. Located in the respiratory system to move mucus. CELLS THAT COVER AND LINE BODY ORGANS Transport. Flagella Propels the cell. The only flagellated cell in the human body is the sperm. Epithelial Cells Packs together in sheets. Intermediate fibers resist tearing during rubbing or pulling. Is the lining of organs. Microvilli Tiny, fingerlike extensions of the plasma membrane that increases surface area for absorption. Smaller than cilia. Absorption. Cell diversity Pseudo (fake) stratified is not stratified as it The human body houses over 200 only has one layer. different cell types. Transitional epithelium lines the urinary bladder. Cells vary in size, shape, and function. Cells that move organs and body parts Cells vary in length from 1/12,000 of an inch to over 1 yard (nerve cells). Cell shape reflects its specialized function. Cells that connect body parts Skeletal muscle and smooth muscle cells are contractile filaments allow cells to shorten forcefully. The heart, although a muscle, has cardiac muscle cells. Skeletal muscle are straited, a muscle tissue that features repeating functional units called sarcomeres. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Cells that store nutrients Membrane transport Fat Cells Solution is a homogenous mixture of two or Lipid droplets stored in the cytoplasm. Fats more components. also provide insulation and thermal Solvent is the dissolving medium present in regulation. a larger quantity; the body’s main solvent is water. Solutes are components in smaller quantities within a solution. Intracellular fluid Nucleoplasm and cytosol. Cells that fight diseases Solution containing gases, nutrients, and salts dissolved in water. Extracellular fluid (interstitial fluid) Fluid on the exterior of the cell. Contains thousands of ingredients such as nutrients, hormones, neurotransmitters, White blood cells, such as macrophage salts, and waste products. (a phagocytic cell), digests infectious microorganisms. Plasma membrane Cells that gather information and control body The plasma membrane is a selectively function permeable barrier. Nerve cell or neurons Some materials can pass through, while Received and transmits messages to other others are excluded. E.g. nutrients can body structures. enter the cell while undesirable substances are kept out. Methods of membrane transport Passive processes Substances are transported across the Cells of reproduction membrane without any input from the cell Oocyte Active processes Largest cell in the body. Divides to become and embryo upon fertilization. The cell provides the metabolic energy (ATP) to drive the transport process Sperm Built for swimming to the egg for The majority of ATP synthesis occurs in fertilization. Flagellum acts as a motile cellular respiration within the mitochondrial whip. matrix: generating approximately thirty-two ATP molecules per molecule of glucose that is oxidized. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Simple diffusion PASSIVE PROCESSES DIFFUSION An unassisted process Molecule movement is from high Solutes are lipid-soluble or small enough to concentration to low concentration, down a pass through membrane pores concentration gradient. Small amounts of Particles tend to distribute themselves vitamins are required in evenly within a solution. the diet to promote growth, reproduction, Kinetic energy (energy of motion) causes and health. Vitamins A, the molecules to move about randomly. D, E, and K are called the fat-soluble vitamins, Size of the molecule and temperature because they are affect the speed of diffusion. soluble in organic solvents and are absorbed and transported in a manner similar to that of fats. (ADEK - Lipid Soluble vitamins) Osmosis Molecules will move by diffusion if any of Simple diffusion of water across a the following applies: selectively permeable membrane The molecules are small enough to pass through the membrane’s pores Highly polar water (channels formed by membrane molecules easily cross the proteins) plasma membrane through aquaporins. The molecules are lipid-soluble Water moves down its The molecules are assisted by a concentration gradient. membrane carrier Kidney: organ that’s good in filtration. Vesicles: Vesicles are involved in metabolism, transport, buoyancy control, and enzyme storage. They can also act as chemical reaction chambers. TYPES OF DIFFUSION Isotonic solutions have the same solute and water concentrations as cells and The three types of diffusion are - simple cause no visible changes in the cell diffusion, osmosis and facilitated diffusion. (equal component = nothing will happen). Hypertonic solutions contain more solutes than the cells do; the cells will Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes begin to shrink (more solute than solvent The membrane may lack special = cells will shrink) protein carriers for the transport of certain substances. Hypotonic solutions contain fewer Substances may not be lipid-soluble. solutes (more water) than the cells do; Substances may have to move against cells will plump (less solute more solvent = a concentration gradient. cells will swell) Through cellular respiration. Facilitated diffusion Active Transports lipid-insoluble and large Active transport substances. Glucose is transported via facilitated diffusion. Protein membrane Amino acids, some sugars, and ions are channels or protein molecules that act as transported by protein carriers known as carriers are used. solute pumps ATP energizes solute pumps In most cases, substances are moved against concentration (or electrical) gradients. Sodium-potassium pump Necessary for nerve impulses. Sodium is transported out of the cell. Potassium is transported into the cell. Filtration Water and solutes are forced through a membrane by fluid, or hydrostatic, pressure. A pressure gradient must exist that pushes solute-containing fluid (filtrate) from a high- pressure area to a lower-pressure area. Filtration is critical for the kidneys to work properly. ACTIVE PROCESSES Vesicles are involved in metabolism, transport, buoyancy control, and enzyme ATP is used to move substances across a storage. They can also act as chemical membrane reaction chambers. Active processes are used when: Substances are too large to travel through membrane channels Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Vesicular transport Endocytosis Substances are moved across the membrane “in bulk” without actually Extracellular substances are enclosed crossing the plasma membrane. (engulfed) in a membranous vesicle. Types of vesicular transport Vesicle detaches from the plasma membrane and moves into the cell. Exocytosis (Release) Endocytosis (Engulf) Once in the cell, the vesicle typically fuses Phagocytosis with a lysosome. Pinocytosis Contents are digested by lysosomal Endocytosis is the process by which enzymes. substances are engulfed into the cell. In some cases, the vesicle is released by Exocytosis is the reverse; the process by exocytosis on the opposite side of the cell. which substances are released from the cell. Phagocytosis — “cell eating” Exocytosis Cell engulfs Mechanism cells use to actively secrete large particles hormones, mucus, and other products. such as bacteria Material is carried in a membranous sac or dead body called a vesicle that migrates to and cells. combines with the plasma membrane. Pseudopods are Contents of vesicle are emptied to the cytoplasmic extensions that separate outside. substances (such as bacteria or dead body cells) from external environment. Phagocytosis is a protective mechanism, not a means of getting nutrients. Pinocytosis —“cell drinking” Cell “gulps” droplets of extracellular fluid containing dissolved proteins or fats. Exocytosis Docking Plasma membrane forms a pit, and edges Process fuse around droplet of fluid. Docking proteins on Routine the vesicles recognize activity for plasma membrane most cells, proteins and bind with such as them. those involved in Membranes corkscrew absorption and fuse together. (small intestine). Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes CELL DIVISION Events of cell division Cell life cycle is a series of changes the cell Mitosis experiences from the time it is formed until it divides. Division of the nucleus. Results in the formation of two Cell life cycle has two major periods: daughter nuclei. Interphase (metabolic phase) Cytokinesis Cell grows and carries on metabolic Division of the cytoplasm. processes. Begins when mitosis is near completion. Longer phase of the cell cycle. Results in the formation of two Cell division daughter cells. EVENTS OF MITOSIS Cell reproduces itself PROPHASE Preparations: DNA Replication Genetic material is duplicated and readies Chromatin coils into chromosomes; a cell for division into two cells. identical strands called chromatids are held together by a centromere. Occurs toward the end of interphase. Centrioles direct the assembly of a mitotic Process of DNA replication spindle. DNA uncoils into two nucleotide chains, Nuclear envelope and nucleoli have broken and each side serves as a template down. Nucleotides are complementary Nuclear membrane breakdown results to the creation of a mitotic spindle. METAPHASE Adenine (A) always Chromosomes are aligned in the center of bonds with the cell on the metaphase plate (center of Thymine (T) the spindle midway between the centrioles). Guanine (G) always Straight line of chromosomes is now seen. bonds with Cytosine (C) Alignment of chromosomes. e.g. Anaphase TACTGC Centromere splits. bonds with new Chromatids move slowly apart and towards nucleotides the opposite send of the cell. in the order ATGACG Anaphase is over when the chromosomes stop moving. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes TELOPHASE In some cases, the cytoplasm is not divided: Reverse of prophase. Binucleate or multinucleate cells result. Chromosomes uncoil to become chromatin. Common in the liver and skeletal muscle. Spindles break down and disappear. Nuclear envelope re-forms around chromatin. Nucleoli appear in each of the daughter nuclei. Cytokinesis Division of the cytoplasm. Begins during late anaphase and completes during telophase. A cleavage furrow (contractile ring of PROTEIN SYNTHESIS microfilaments) forms to pinch the cells into two parts. DNA serves as a blueprint for making proteins Two daughter cells exist. Gene Summary Chromatin coils DNA segment that carries a blueprint for into chromosomes. building one protein or polypeptide chain Prophase Centrioles direct the assembly of a Proteins have many functions mitotic spindle. Chromosomes are Fibrous (structural) proteins are the Metaphase aligned in a center. building materials for cells. Centromere splits Anaphase (cleavage) Globular (functional) proteins can act Reverse of as enzymes (biological catalysts). prophase. Telophase DNA information is coded into a sequence Chromosomes uncoil. of bases. Division of the Cytokinesis A sequence of three bases (triplet) codes cytoplasm. for an amino acid. Mitosis or meiosis is important because: growth and reproduction. For example, a DNA sequence of AAA specifies the amino acid phenylalanine. In most cases, mitosis and cytokinesis occur together. The role of DNA Most ribosomes, the manufacturing sites of proteins, are located in the cytoplasm. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes DNA never leaves the nucleus in Translation interphase cells. Base sequence of nucleic acid is translated DNA requires a decoder and a messenger to an amino acid sequence; amino acids to carry instructions to build proteins to are the building blocks of proteins. ribosomes. Occurs in the cytoplasm and involves three Both the decoder and messenger functions major varieties of RNA. are carried out by RNA (ribonucleic acid). Steps correspond to Figure 3.16 (step 1 How does RNA differ from DNA? covers transcription) ○ Step 2: mRNA leaves nucleus and RNA is single-stranded. attaches to ribosome, and translation RNA contains ribose sugar instead of begins deoxyribose. ○ Step 3: incoming tRNA recognizes a RNA contains uracil (U) base instead of complementary mRNA codon calling for its thymine (T). amino acid by temporarily binding its anticodon to the codon Three varieties of RNA Step 4: as the ribosome moves along the Transfer RNA (tRNA) mRNA, a new amino acid is added to the Transfers appropriate amino acids to the growing protein chain ribosome for building the protein. Step 5: released tRNA reenters the Ribosomal RNA (rRNA) cytoplasmic pool, ready to be recharged with a new amino acid Helps form the ribosomes where proteins are built. Messenger RNA (mRNA) Carries the instructions for building a protein from the nucleus to the ribosome. Phases of protein synthesis Transcription Transfer of information from DNA’s base sequence to the complementary base sequence of mRNA. DNA is the template for transcription; mRNA is the product. Each DNA triplet corresponds to an mRNA codon. If DNA sequence is AAT-CGT-TCG, then the mRNA corresponding codons are UUA- GCA-AGC. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Chapter iii. body tissues Shape of cells Epithelial Tissues Groups of cells with similar structure and function. Four primary types Epithelial tissue (epithelium) Connective tissue Muscle tissue Nervous tissue EPITHELIAL TISSUE/ epithelium Locations Squamous—flattened, like fish scales Body coverings Body linings Cuboidal—cube-shaped, like dice Glandular tissue Columnar—shaped like columns Functions Protection Absorption Filtration Secretion Hallmarks of epithelial tissues Cover and line body surfaces. SIMPLE EPITHELIA Often form sheets with one free surface, the apical surface, and an anchored Functions in absorption, secretion, and surface, the basement membrane. filtration Avascular (no blood supply). Very thin (so not suited for protection) Regenerate easily if well nourished. SIMPLE SQUAMOUS EPITHELIUM Classification of epithelia Single layer of flat cells Locations—usually forms membranes Number of o Lines air sacs of the lungs cell layers o Forms walls of capillaries o Forms serous membranes Simple— (serosae) that line and cover one layer organs in ventral cavity Stratified— Functions in diffusion, filtration, or more than one secretion in membranes layer Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes PSEUDOSTRATIFIED COLUMNAR EPITHELIUM All cells rest on a basement membrane. Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification. SIMPLE CUBOIDAL EPITHELIUM Location Single layer of cubelike cells. respiratory tract, where it is ciliated and known as pseudostratified Locations ciliated columnar epithelium Common in glands and their ducts Functions in absorption or secretion. Forms walls of kidney tubules Covers the surface of ovaries Functions in secretion and absorption; ciliated types propel mucus or reproductive cells. Stratified epithelia Consist of two or more cell layers Function primarily in protection SIMPLE COLUMNAR EPITHELIUM Stratified squamous epithelium Single layer of tall cells. Most common stratified epithelium Goblet cells secrete mucus. Named for cells present at the free Locations (apical) surface, which are squamous Lining of the digestive tract from Functions as a protective covering where stomach to anus friction is common Mucous membranes (mucosae) Locations—lining of the: line body cavities opening to the exterior Skin (outer portion) Mouth Functions in secretion and absorption; Esophagus ciliated types propel mucus or reproductive cells. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Stratified cuboidal epithelium Exocrine glands Two layers of cuboidal cells; functions in Secretions empty through ducts to the protection. epithelial surface. Stratified columnar epithelium Include sweat and oil glands, liver, and pancreas (both internal and external). Surface cells are columnar, and cells underneath vary in size and shape; CONNECTIVE TISSUE functions in protection. Found everywhere in the body to connect Stratified cuboidal and columnar body parts. Includes the most abundant and widely Rare in human body distributed tissues. Found mainly in ducts of large glands Functions: Transitional epithelium Protection Composed of modified stratified squamous Support epithelium Binding Shape of cells depends upon the amount Characteristics of connective tissue of stretching Variations in blood supply Functions in stretching and the ability to return to normal shape Some tissue types are well vascularized Location: lining of urinary system organs Some have a poor blood supply or are avascular Extracellular matrix Nonliving material that surrounds living cells Two main elements of the extracellular matrix Ground substance Glandular epithelia Mostly water, along with adhesion proteins One or more cells responsible for secreting and polysaccharide molecules. a particular product. Fibers Secretions contain protein molecules in an aqueous (water-based) fluid. Collagen (white) fibers Elastic (yellow) fibers Secretion is an active process. Reticular fibers (a type of collagen) Two major gland types develop from epithelial sheets Types of connective tissue from most rigid Endocrine glands to softest, or most fluid: Ductless; secretions (hormones) diffuse Bone into blood vessels. Examples include Cartilage thyroid, adrenals, and pituitary. Dense connective tissue Loose connective tissue Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Blood Bone (osseous tissue) Composed of: Osteocytes (bone cells) sitting in lacunae (cavities) Hard matrix of calcium salts Elastic cartilage (not pictured) Large numbers of collagen fibers Provides elasticity Functions to protect and support the body. Location: supports the external ear Fibrocartilage Highly compressible Location: forms cushion-like discs between vertebrae of the spinal column Cartilage Less hard and more flexible than bone Found in only a few places in the body Chondrocyte (cartilage cell) is the major cell type Dense connective tissue (dense fibrous tissue) Types Hyaline cartilage Main matrix element is collagen fiber Fibrocartilage Fibroblasts are cells that make fibers Elastic cartilage Locations Hyaline cartilage Tendons—attach skeletal muscle to Most widespread type of cartilage bone Ligaments—attach bone to bone at Abundant collagen fibers hidden by a joints and are more elastic than glassy, rubbery matrix. tendons Locations Dermis—lower layers of the skin Trachea Attaches ribs to the breastbone Covers ends of long bones Entire fetal skeleton prior to birth Epiphyseal (growth) plates in long bones Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Loose connective tissue Softer, have more cells and fewer fibers than other connective tissues (except blood) Types Areolar Adipose Reticular Reticular connective tissue Areolar connective tissue Delicate network of interwoven fibers with reticular cells (like fibroblasts) Most widely distributed connective tissue Forms stroma (internal framework) of Soft, pliable tissue like “cobwebs” organs Functions as a universal packing tissue Locations and “glue” to hold organs in place Lymph nodes Layer of areolar tissue called lamina Spleen propria underlies all membranes Bone marrow All fiber types form a loose network Can soak up excess fluid (causes edema) Blood (vascular tissue) Blood cells surrounded by fluid matrix Adipose connective tissue known as blood plasma An areolar tissue in which adipose (fat) Soluble fibers are visible only during cells dominate clotting Functions Functions as the transport vehicle for the cardiovascular system, carrying: Insulates the body Protects some organs Nutrients Serves as a site of fuel storage Wastes Respiratory gases Locations Subcutaneous tissue beneath the skin Protects organs, such as the kidneys Fat “depots” include hips, breasts, and belly Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes MUSCLE TISSUE Function is to contract, or shorten, to produce movement. Three types of muscle tissue: Skeletal Cardiac Smooth Smooth (visceral) muscle tissue Skeletal muscle Involuntarily controlled Packaged by connective tissue sheets into Found in walls of hollow organs such as skeletal muscles, which are attached to the stomach, uterus, and blood vessels skeleton and pull on bones or skin. Peristalsis, a wavelike activity, is a typical Voluntarily (consciously) controlled. activity Produces gross body movements or facial Characteristics of smooth muscle cells expressions. No visible striations Characteristics of skeletal muscle cells One nucleus per cell Spindle-shaped cells Striations (stripes) Multinucleate (more than one NERVOUS tissue nucleus) Function is to receive and conduct Long, cylindrical shape electrochemical impulses to and from body parts. Irritability Conductivity Composed of neurons and nerve support cells. Support cells called neuroglia insulate, protect, and support neurons. Cardiac muscle tissue Involuntarily controlled Found only in the heart Pumps blood through blood vessels Characteristics of cardiac muscle cells Striations One nucleus per cell Short, branching cells Intercalated discs contain gap junctions to connect cells together Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes TISSUE REPAIR (WOUND HEALING) Clean cuts (incisions) heal more Tissue repair (wound healing) occurs in two successfully than ragged tears of the ways: tissue. Regeneration: Replacement of destroyed tissue by the same kind Events of tissue repair of cells Fibrosis: Repair by dense (fibrous) Inflammation sets the stage connective tissue (scar tissue) Capillaries become very permeable. Whether regeneration or fibrosis occurs depends on: Clotting proteins migrate into the area from Type of tissue damaged the bloodstream. Severity of the injury A clot walls off the injured area. Carl Christian Caduhada | [email protected] | University of St. La Salle BBIO 302 HUMAN ANATOMY AND PHYSIOLOGY Lecture Notes Granulation tissue forms Injury can severely handicap amitotic tissues. Growth of new capillaries. The cause of aging is unknown, but Phagocytes dispose of blood clot and chemical and physical insults, as well as fibroblasts. genetic programming, have been proposed as possible causes. Rebuild collagen fibers Neoplasms Regeneration and fibrosis effect permanent repair Both benign and cancerous, represent abnormal cell masses in which normal Scab detaches controls on cell division are not working. Whether scar is visible or invisible depends Hyperplasia on severity of wound (Increase in size) of a tissue or organ may occur when tissue is strongly stimulated or Tissues that regenerate easily irritated. Epithelial tissue (skin and mucous Atrophy membranes) (Decrease in size) of a tissue or organ Fibrous connective tissues and bone occurs when the organ is no longer stimulated normally Tissues that regenerate poorly Skeletal muscle Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord. Developmental Aspects of Cells and Tissues Growth through cell division continues through puberty. Cell populations exposed to friction (such as epithelium) replace lost cells throughout life. Connective tissue remains mitotic and forms repair (scar) tissue. With some exceptions, muscle tissue becomes amitotic by the end of puberty. Nervous tissue becomes amitotic shortly after birth. Carl Christian Caduhada | [email protected] | University of St. La Salle